Natural Resources and Environment Minister Surasak Kanjanarat wants to introduce a plan to charge waste water treatment fees to households and tourists, as part of the ministry's efforts to clean up rivers and canals countrywide, including the Saen Saep canal in the capital.

At a meeting on water treatment for the Saen Saep canal, Gen Surasak said Prime Minister Prayut Chan-o-cha's initiative to clean the canal will be put into action between 2017-2018, as all stakeholders have agreed to work together by focusing on enforcing the law against pollution sources.

Saen Saep is a main canal in Bangkok used for drainage and transportation. It is linked to more than 100 sub-canals.

Between October 2015 and this month, the department inspected 210 out of the 631 pollution sources and found more than half of the condominiums discharged waste water not in line with the law.

Forty per cent of hotels, 23% of hospitals and 20% of department stores also discharged waste water in a way that contravened the law.

"Within two years, we will fully enforce the law to limit polluted water entering the canal," Gen Surasak said.

"Extra charges for tap water users, including tourists, for waste water treatment will be introduced. This is not only for the Saen Saep canal, but also for all [water resources] countrywide."

"If we do nothing, all rivers and canals in the next 20 years will be completely ruined. And if you are not ready to pay now, you might have to pay more in the future."

He said it would be possible that waterworks authorities will be key agencies to collect the waste water treatment fee from households countrywide.

The department's study showed that a possible charge would be 0.43 baht per cubic metre.

This will bring in 5.275 billion baht revenue per year. Plans have been made to charge each tourist 50 baht for waste water treatment which will bring in 1.494 billion baht of revenue each year.

The figure was calculated from the number of 29.88 million tourists who visited Thailand last year. The Immigration Office would be in charge of fee collection.

Pollution Control Department chief Jatuporn Buruspat said the department will strengthen efforts to examine wastewater treatment in 21 districts involved with the 100 sub-canals linked to the Saen Saep canal, adding that Ministry of Interior is in charge of communities living along the canal.